Treatment of catalytic reformates



joint-stock corporation No Drawing. Filed May 11, 1959, Ser. No. 812,139 Claims priority, application Great Britain May 23, 1958 6 Ciaims. (Cl. 200-79) This invention relates to the treatment of the products of a catalytic reforming process, hereinafter referred to as catalytic reformates.

In catalytic reforming processes, a naphtha fraction is contacted at elevated temperature and pressure and in the presence of hydrogen with a dehydrogenation catalyst to produce a gasoline fraction of increased octane number. Catalysts that are used commercially include molybdenum oxide on alumina and catalysts consisting essentially of platinum on alumina with or without combined halogen. A catflytic reforming process using a platinum-onalumina type catalyst will hereinafter be referred to as platinum reforming and the products as platinum reformates.

Platinum reforming is capable of giving products with octane numbers research (clear) of the order of 90-100, but it has certain limitations. In the first place, beyond a certain octane level, increase in octane number is only obtainable at the expense of decreased volatility and this runs contrary to the present emphasis on gasolines having both high octane number and high volatility. While adjustment of the feedstock boiling range can improve product volatility, treatment of lower-boiling feedstocks requires high operating severity and gives lower yields. In the second place, there is a practical upper limit of octane number, quite irrespective of volatility.

According to the present invention, a catalytic reformate is separated into a higher-boiling fraction and a lower-boiling fraction, at least the higher-boiling fraction is contacted at from 840 to 1075 F. (450 to 580 C.) with a dehydrogenation and dehydrocyclisation catalyst to yield a product of increased volatility and the treated higher-boiling fraction is recombined either with the untreated lower-boiling fraction or with the lower-boiling fraction after it has also been contacted at elevated temperature with a dehydrogenation and dehydrocyclisation catalyst to yield a product of increased octane number.

The higher-boiling fraction of a catalyst reformate is relatively rich in aromatics andis not, prima facie, a suitable material for further upgrading by dehydrogenation and dehydrocyclisation. However, such a treatment gives a product of increased volatility. The octane number can also be increased further. By blending this treated higher-boiling fraction back with the untreated lowerboiling fraction, a final product is obtained of increased volatility and also, usually, increased octane number. Preferably the product has a volatility of at least 40% volume evaporated at 100 C., particularly from 40 to 60%, and an octane number research (clear) of at least 90. e

' The product may be used as a component of motor gasolines, but the process is particularly suitable for the production of high octane number, high volatility motor gasolines themselves which do not require the addition of further blending components.

In a further specific embodiment of the present invention both the higher-boiling'and the lower boiling fractions are contacted separately with a dehydrogenation and dehydrocyclisation catalyst and the fractions are re-combined. Preferably the recombined blend has an octane number research (clear) of at least 100. It has been found that higher octane numbers are obtain- 3,033,777 Patented May 8, 1902 able at a given reactionv temperature when compared with a single treatment of the whole of a catalytic reformate. Further while the treatment of the lower-boiling fraction decreases its volatility, this is ofiset' at least in part by the increase in volatility of the treated higher-boiling fraction, and a higher octane number is obtainable at a given volatility, or vice versa, than, when treatingfthe whole of a catalytic reformate.

The preferred dehydrogenation and dehydrocyclisation catalyst for treating both the higher-boiling and lower boiling fractions consists essentially of chromium oxide supported on alumina. It ispreferably used ata pressure of up to 50 p.s.i.g. (including atmospheric pressure or below) and without recycle of the hydrogen-rich gas produced or addition of extraneous hydrogen-rich gas produced or addition of extraneous hydrogen. The space velocity may be from 0.1 to 1.0 v./v./hr. of liquid feedstock. The chromia on alumina catalyst may contain a minor proportion of oneor more promoters, for example a rare earth or mixture of rare earths,- bismuth, boron, germanium, nickel, man anese, iron or beryllium preferably in combination with an alkali metal, such, as potassium. Another particularly etfective promoteris a minor proportion of a spinel, for example cobalt, chromite, copper chromite, zinc titanate, or iron chromite, either as such or in the form of the naturally-occurring ore chrome ironstone.

The preferred proportions of the catalyst, by weight of total catalyst stable at 1020 F.,are:

Chromium oxide 5-25 wt. Total promoters (expressed as oxide in the case of The dehydrogenation and dehydrocyclisation process may be carried out with a fixed bed, a moving bed or a fluidised bed of catalyst. With the preferred catalyst,

which can be readily regenerated by conventional techniques, a fluidised bed is-preferred.

The preferred catalytic reformate used as feed stock is a platinum reformate.

The platinum reformate is preferably produced by a platinum reforming process using a heavy naphtha'feedstock and operating under conditions such that regeneration of the catalyst in situ is not required (i.e. a catalyst life of at least 40 barrels of feedstock processed per lb. of catalyst).

The term heavy naphtha means anaphtha having an ASTM final. boiling point between 150 C. and 200 C. and, preferably, an ASTM initial boiling point within the range 70 C. to C. p

The platinum reforming stage is preferably operated to give a reformate having an octane number research (clear) of'90 to 100. Any convenient platinurnreforming process may be used and the process conditions will normall'yifall within'the following ranges:

Catalyst n.-- 01-10% wt. platinum on alumina withor without-0.1-8% wt. of halogen, particularly fluorine and/or chlorine.

Temperature 60.0 1200 preferably 9004000 F. 504000 p.s'.i., preferably 300-700 7 characteristics shown in Table 2.

The'higher-boiling fraction of the catalytic reformate should contain the majority of the alkyl aromatics in the reformate. A convenient separation point is in the range 80l30 0., more particularly within the range 100-120 C. The separation may be efiected by simple distillation.

The invention is illustrated by the following examples.

EXAMPLE 1 i A naphtha of Middle East origin having an ASTM boiling range of 90-171" C. was reformed using a catalyst of 0.7% wt. platinum, 0.45% Wt. fluorine and 0.34% wt. chlorine on alumina to a research octane level of 93. The reforming conditions used were 925 F., 500' p.s.i.g., 10 v./v./hr. and a hydrozen/hydrocarbon'mol 'ratio of 10:1. The platinum reiormate so produced was fractionated at 100 C. to 'give a lower-boiling fraction having an ASTM boiling range of 43 97.5 C. and an octane number research (clear) of 69.2 and a higher- 'boiling fraction having an IBP of 115 C. and an octane number research (clear) of 101.9. The lower-boiling fraction represented 34.4% wt. and the higher-boiling fraction 65.6% wt. of the platinum reformate.

The higher-boiling fraction was treated over a fixed bed of a catalyst consisting of 10% Wt. chromia on alumina promoted with 1% wt. cerium oxide and 1% wt.

potassium oxide under the following conditions:

Pressure Atmospheric. Space velocity 0.2 v./v./hr. Recycle gas None. .Process period 5 hours.

Runs were carried out at two different temperatures lower-boiling fraction having an ASTM boiling range of 34-108 C. and an octane number research (clear) of 76.1 and a higher-boiling fraction having an ASTM boiling range of 128-216 C., and an octane number research (clear) of 104.6. The lower-boiling fraction represented 41.2% wt. and the higher-boiling fraction 58.8% wt. of the platinum reformate.

The higher-boiling fraction was treated under the same conditions and with the same catalyst as that used in Example 1.

Runs were carried out at four different temperatures and the results are set out in Table 3 below.

Table 3 Reaction temperature F. Feed Yield on feed, percent weight 100 86. 0 84. 0 79. 0 77. 0 Specific gravity at 60 F./

60F 0. 8505 0.8700 0.8730 0.8755 '0. 8765 Volatility at 140 0., per

ccn vol 20.0 38.0 34.0 33.0 57.0 Octane number research a (clear) 104.0 111.0 112.2 112.2 112.8

The treated higher boiling fractions were then blended back with the lower-boiling fraction. The blends again had an increased volatility and octane number as shown in Table 4.

Table 4 Untreated Heavy end treated at platinum refer-mate 887 F. 932 F. 977 F. 1,022 F.

Yield on total platinum 7 retorrnate, percent 7 Weight 100 93. 2 92. 1 90. 0 89. 0 Volatility at 100 0.,

percent vol 39. 5 51. 8 52. 4 53. 8 54. 5 Octane number research (clear) 92. 8 -95. 6 06. 3 95. 8 95. 0

EXAMPLE 3 Comparative experiments were carried out in which the whole of the platinum reformate of Example 2, and the higher-boiling fraction and the lower-boiling .fractions (also as obtained in Example 2) were treated separately under the same conditions and with the same catalyst as that used in Example 1. The treated higher- The treated higher-boiling fractions were then blended" back with the lower-boiling fraction. The blends had the Table 2 Heavy end Heavy end treated at treated a 932 F. 1022 F.

Untreated 7 relormate From the table it will 'be seen that the volatility of the final product and also the o'ctane number has been increased as compared with the original platinum reformate. 7

EXAMPLE 2 and lower-boiling fractions were subsequently re-combined.

The reaction temperatures used and the results obtained are set out in Table 5 below.

Table 5 Treating total platinum reformate Reaction temperature 1:. Feed Yield on feed, percent weight. 86 83 70 Volatility at 100 0., percent volume... 39. E 32. 6 33. 6 27 Octane number research (clear) 92. 8 100. 4 102. 3 103. 5

Treating lower-boiling fraction (SG 0.69)-Yield on total reformate 53.6% vo1., 41.2% weight Yield on feed, percent weight. i 1 72. 6 01. 6 67. 0 Volatility at 100 0., percent vol. 74 67. 2 62:0 59. 0 seat; 60 E F- 7360 7610 .7900 .7970 Octane number research (clear) 94.3 90.0 102.1 103.0

5)-Yie1d on total reformate Treating higher-boiling traction '(SG .856

I a weight 46.5% VOL, 58.8 0

Octane number research (clea Blend of treated hlgherand lower-boiling fractions-Blended in make ratio on total reiormate Yield on total relormate, percent From the table it will be seen that at a reaction temperature of 887 F. the blended product has a somewhat higher octane number and a considerably higher volatility than the treated total reformate. At the higher reaction temperatures the two products are of equivalent volatility but the blended product has a considerably higher octane number.

We claim:

1. A process for the treatment of a catalytic reformate to produce a product having a high octane number and high volatility which comprises separating the catalytic reformate into a high boiling fraction and a low boiling fraction, the cut point between the fractions being in the range 80 to 130 C., contacting the high boiling fraction in a reaction zone with a dehydrogenation and dehydrocyclization catalyst consisting essentially of to 25% wt. of chromium oxide by weight of total catalyst stable at 1020 F., and balance alumina, at a temperature of 840 to 1075 F., at a pressure not in excess of 50 p.s.i. ga., at a space velocity of 0.1 to 1.0 v./v./hr., and in the absence of added hydrogen, recovering the treated high boiling fraction, and combining the low boiling fraction with said treated high boiling fraction to produce a product having an octane number research (clear) of at least 90 and a volatility of at 'least 40% volume evaporated at 100 C.

2. A process for the treatment of a catalytic reformate to produce a product having a high octane number and high volatility which comprises separating the catalytic reformate into a high boiling fraction and a low boiling fraction, the cut point between the fractions being in the range 80 to 130 C., contacting the high boiling fraction in a reaction zone with a dehydrogenation and dehydrocyclization catalyst consisting essentially of 5 to 25% wt. of chromium oxide, by weight of total catalyst stable at to 1075 F., at a pressure not in excess of p.s.i. ga., at a space velocity of 0.1 to 1.0 v./v./hr., and in the absence of added hydrogen, recovering the treated high boiling fraction, contacting the separated low boiling fraction in a reaction zone With a dehydrogenation and dehydrocyclization catalyst consisting essentially of 5 to 25% wt. of chromium oxide, by weight of total catalyst stable at 1020 F., and balance alumina, at a temperature of 840 to 1075 F., at apressure not in excess of 50 p.s.i. ga., at a space velocity of 0.1 to 1.0 v./v./hr., and in the absence of added hydrogen, recovering the treated low boiling fraction, and combining the treated fractions to produce a product having an octane number research (clear) of at least 100, and a volatility at least substantially equal to the volatility of the catalytic reformate.

3. A process in accordance with claiml wherein the catalyst includes at least one promoter in an amount of 0.1 to 10% wt. by weight of total catalyst stable at 1020 F., said weight of promoter being less than the weight of the chromium oxide.

4. A process in accordance with claim 2 wherein the catalyst includes at least one promoter in an amount of 0.1 to 10% wt. by weight of total catalyst stable at 1020" F., said weight of promoter being less than the weight of the chromium oxide.

5. A process in accordance with claim 1 wherein the catalytic reformate is a platinum reformate.

6. A process in accordance with claim 5, wherein the platinum reformate is produced by a process using a heavy naphtha feedstock and operating under conditions such that the regeneration of the catalyst in situ is not required.

References Cited in the file of this patent UNITED STATES PATENTS Knight July 28, 1959 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No, 3,033,777 May 8 1962 John Arthur Edgar Moy et a1.

It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent ehould read as corrected below.

Column 1, line 48, for "catalyst" read catalytic column 2, line 24, after "cobalt strike out the comma; line 66, before "50-1000" insert Pressure-- column 3, line 15, for "10 v.,/v,./hr-. and a hydrozen/hydrocarbon" read 100 v.,/v.,/hr*u and a hydrogen/hydrocarbon column 4,

Tabtl e E3, heading to column 2 thereof for "Feed F." read Signed and sealed this 9th day of October 1962.

(SEAL) Attest:

DAVID L. LADD ERNEST W. SWlDER Commissioner of Patents Attesting Officer 

1. A PROCESS FOR THE TREATMENT OF A CATALYTIC REFORMATE TO PRODUCE A PRODUCT HAVING A HIGH OCTANE NUMBER AND HIGH VOLATILITY WHICH COMPRISES SEPARATING THE CATALYTIC REFORMATE INTO A HIGH BOILING FRACTION AND A LOW BOILING FRACTION, THE CUT POINT BETWEEN THE FRACTIONS BEING IN THE RANGE 80 TO 130*C., CONTACTING THE HIGH BOILING FRACTION IN A REACTION ZONE WITH A DEHYDROGEENATION AND DEHYDROCYCLIZATION CATALYST CONSISTING ESSENTIALLY OF 5 TO 25% WT. OF CHROMIUM OXIDE BY WEIGHT OF TOTAL CATALYST STABLE AT 1020*F., AND BALANCE ALUMINA, AT A TEEMPERATURE OF 840 TO 1075*F., AT A PRESSURE NOT IN EXCEESS OF 50 P.S.I. GA., AT A SPACE VELOCITY OF 091 TO 1.0 V./V./HR., AND IN THE ABSENCEE OF ADDED HYDROGEN, RECOVERING THE TREATED HIGH BOILING FRACTION, AND COMBINING THE LOW BOILING FRACTION WITH SAID TREATING HIGH BOILING FRACTION TO PRODUCE A PRODUCT HAVING AN OCTANE NUMBER RESEARCH (CLEAR) OF AT LEAST 90 AND A VOLATILITY OF AT LEAST 40% VOLUME EVAPORATEED AT 100*C. 